Battery SOC Estimation Using Pre-Stabilization Voltage Cycles
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Solution Overview
Problem
Conventional methods for measuring the state of charge (SOC) and energy storage amount of batteries in electric vehicles are inefficient, requiring long times and being unsuitable for real-time applications, with the OCV method being inaccurate in real-time and the coulomb counting method taking several hours.
Innovation Solution
A method involving first and second charging or discharging cycles with voltage measurements before voltage stabilization, using a preset OCV-SOC characteristic curve to calculate SOC values and energy storage amounts, and incorporating coulomb counting to determine energy variance, allowing for rapid determination of battery state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the open circuit voltage (OCV) method is used to measure battery energy storage, then measurement accuracy is excellent when the battery is healthy and OCV is stabilized, but it requires a long time to stabilize the battery voltage before measurement
Solution Approach 1:
The patent performs preliminary charging or discharging cycles to activate the battery and establish a baseline voltage state before the actual measurement. This preliminary action allows the system to calculate SOC based on voltage changes during controlled charging/discharging phases, avoiding the need to wait for natural voltage stabilization while maintaining measurement accuracy.
Solution Approach 2:
The patent employs periodic charging and discharging cycles at controlled rates. By applying periodic electrical stimuli and measuring voltage responses at specific intervals, the system can calculate SOC dynamically without requiring the battery to remain in a static open-circuit state for extended periods, thus reducing stabilization time while preserving accuracy.
2Measurement precision
If the coulomb counting method is used to measure battery energy storage, then measurement of used electric energy is relatively accurate, but it takes at least four to five hours to measure total energy amount
Solution Approach 1:
The patent performs preliminary charging or discharging cycles to establish baseline measurements and activate the battery system before conducting the actual energy storage measurement. This preliminary action enables the system to obtain accurate SOC values more quickly by having the battery in a known, activated state, thereby reducing the total measurement time from 4-5 hours to a shorter duration while maintaining accuracy.
Solution Approach 2:
The patent maintains continuous monitoring and calculation of voltage and current parameters throughout the charging/discharging process. By continuously measuring voltage during controlled charging/discharging cycles and integrating current data, the system can calculate total energy storage amount in real-time without interrupting the process, significantly reducing the measurement time compared to traditional methods that require prolonged static measurement periods.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient and accurate measurement of battery state within a short time, reducing calculation time and improving accuracy for determining charging or replacement times.
Implementation Method 1
Vehicles using the conventional internal combustion engines are deeply related with the generation of pollution such as air pollution, and thus, recently, much effort has been put into the development of electric vehicles or hybrid vehicles using batteries.
Implementation Method 2
measuring a first voltage according to an open circuit of the battery after a first time between a time point immediately after the first charging or discharging and a time point before reaching a voltage stabilization period elapses
Data Source
AI summary
A method of managing a battery is disclosed. The method is capable of efficiently managing a battery by measuring a state of charge (SOC) and an energy storage amount of the battery within a short time. A battery management system and an electric vehicle charging system having the battery management system are also disclosed.